Latch mechanism.



No. 897,514.' PATENTED SEPT. 1, 1908. P. BEER.

LATCH MEGHANISM.

APPLICATION FILED JAN.23, 1907.

IINITED` sTATEs PATENT OEEIOE.

PAUL BEER, or BERLIN, GERMANY, AssIGNOR To 4GENERAL ELECrRIo COMPANY, A CORPORATION OE NEW YORK.

'LATCH MECHANISM.

Specification of Letters Patent.

To all whomitmay concern:

Be it known that I, PAUL BErIR, a subject' of the Emperor of Germany, residing at Berlin, Germany, have invented certain new and useful Improvements in Latch Mechanism, of which the following is a specification.

This invention relates to a trip or latch mechanism and more particularly to latch mechanisms usedin connection with circuit breakers or other pieces of apparatus exposed to shocks or jars or to continuedvibration. The latching mechansim commonly used on circuit breakers consists'of. a pivoted latch having a' hook on one end which engages the locking member and which is held in locking positiony by the friction between the locking .member and the engaging face of the hook, and also by a lightcspring. These latches are usually arranged to be operated by a solenoid lupon the occurrence of an overload and it is necessary that the trip as easily as possible in orderto keep t e size of the solenoid within commercial limits; hence, the .pivoted latch. is provided with a .light spring and -with a form of hook which will release easily. It isr `found, however, that when a circuit breaker provided Witha latch as abovedescribed, is subjected to jars'or to continued vibration, the pressure between the locking-member and the latch varies, owing to the inertia of the parts, andthe inertia of the latch moves it away' from locking position against the light spring, and the circuit 'breaker opens.

The object of my invention isto provide a latch so constructed that -jars or vibration cannot open it, but will onf the contrary cause it to engage'fthe looking member more securely; in which the power for holding the latch in engagement and for throwingthe vlatch out of engagement with the" locking member is furnished by the locking member, and in which the only power required to be vfurnished by the Overload coil is that necesy Y sary to cause an initial movement of the latch, thereby permitting the'juse of a smaller solenoid or overload; coil than is yrequired With latches heretoforein use.

' 'My'invention' in its broadest as ect c onsists of ailatchl mounted so as `tol e moved by thelocking member when `saidV member moves away from its locked position toward unlocked position, and which coperatea `with a supporting or controlling means so constructed that when it Ibears one relation to thelatch thev movement of the latchby uthe locking member will `force the latch into firm engagement with the locking `member,

wh'ile if the relation between the controlling means and the latch is slightly altered, the

movement of thelockin member, carrying the latch in the same irection as before, will force it out of engagement with the locking member and permlt the circuit breaker or other similar piece of apparatus to open.

'Patented sept. 1,'1eo8. i A

If the latch is automatically controlled, an

electromagnetic device may .be furnished for the pur ose ot altering the relation between the lato 1 and the controlling means, and the A only power to be furnishednby the electro# magnetic device is the small amountl required to change the relation of the' latch and the controlling member, the power Afor actually.

moving the latch being supplied by the locking member.

More specifically, my invention consists of a latch, a pivoted member' or crank having a crank pin for the latch and mounted in such a way that when the latch isiin locking position, the crank is slightly over center, but is restrained from going ,any further over'cena ter by some suitable stop yengaging the latch between the crank pin Aand the engaging end of the latch, so that any force tending to move the latch longitudinally and move the crank still more over center, will result i throwing the other end of the latch in the opposite direction andthereby engage still morermlythe locking member with which it cooperates. -A trip coil moves the pivoted member or crank in the other direction until it is beyond center, when the locking member moves the latch longitudinally and into engpgement with means for throwing the loc in end of the latch out, of engagement with t le locking member.

Other features of the vinvention will be tablymounted in 'theframe of the circuit upward and engages a tripping pin 12, when and which, as a result of said movement, will mechanism has been applied.

a frame 13 secured to the base of the circuit Figurel is a'front view and Fig. 2 is a side view of a well known type of circuit breaker to which one form of my improved latching My invention may be embodied in many different forms an'd the form shown in Jthe drawing is simply for the purpose of illustration.

The circuit breaker, which is of a well known type, is mounted on a switchboard 1, and `consists of a movable main contact 2,V copper shifnt contacts 3, and carbon shunt contacts 4; these contacts being mounted upon a rocking arm 5 pivoted to the base of the circuit breaker and actuated atoggle formed by a link 6 and an o craving handle 7, the latter being keyed to a shaft 8 rotabreaker. An overload coil 9 having a Calif' brating device 10 and a core 11 which moves the current fiowing through the overload coil reaches a predetermined limit, is mounted in breaker. The rocking aim 5 is providedwith .a lug or stop 14, which, when thewcircuit breaker is open, engages a spring bu'fler 15 mounted upon the operating handle 7.

On the end ofthe shaft S lis keyed a locking member or arm 16 which, when the circuitI breaker is inthe closed position, is engaged by a hook 17, carried by a latch 18. 'lhe latch 18 is carried upon a controlling or supporting means which will ermit a longitudinal movement of the latc i when the locking member 16. moves from its locked position in a direction to open th'e circuit breaker,

force the latch either toward latching osi tion, into firmer engagement with the loc ring member 16, or away from latching position to release the member 16 and open the breaker, the direction of the movement of the latchdepending on the relation between the latch 18'and the controlling means.

In the embodiment of the invention shown in the drawings, the controlling means con sists of a pivoted member or crank 2() to which the'latch 18 is attached by means of af crank in 19, and. which, in turn, is firmly secured) to a shaft 21 carrying an arm 22, preferably at right angles' to the crank 20, so that the crank 20 and the arm 22` form, in effect, a bell-crank lever mounted u on the shaft 21 while the crank 20 and the atch 18 form, in effect, a two link tripping toggle which is overset when in the position shown in Figsl and 2.

Spiral spring 23, surrounding the shaft 21, has one end engaging the crank 20 and the other engaging one of the supports 24 in which the shaft 2l; is suitably. mounted. This spring tends to hold the parts in normal position sothatv the hook 17 will be in engage-A the shaft is engaged by the latch 18 as shown in Fig. 2 yof the drawings, and forms a stop which prevents further movement of the crank pin 19 to the left unless the latch 18 swings about the shaft 21 as a ivot, thereby throwing the hook 17 into iimer engagement with the locking member 16. A stud or pin 25, of such a length, as shown in Fig. 1, that it extends beyond the path followed by the latch 17, Vis mounted on the frame 13 in such a position that when the latch is in locking position, there is considerable clearance between the surface of the latch and the pin.

The operation of the device is as follows gages tlie latch 18 and prevents movement ofl the upper end of the latch to the left. Any longitudinal movement therefore, will result in throwing the hook 18 to the right and into still firmer engagement with the locking member 16, since the latch 18 will swing about the shaft 21 as a pivot. If the circuit breaker is subjected to jaror vibration, "the latch 18 will tend to swing about pin 19l as a pivot, but the only way.in which it is free to swing is toward the locking member 16, and this is the direction in which it is urged by any pressure upon the hook 17'; hence, all the forces acting upon the latch 18 when in normal position tend to move it toward locking position. If an overload comes upon the circuit the core 11 is attracted and engages and raises the tripping pin 12 which engages the arm 22 and 'throws the crank 2() to the right. l This movement is slight and requires nal movement to the latch 17 and rotate the;

crank 20 to the right, the only resistance 'to the rotation being that due to the spiral spring 23, while the only work performed by the overload coil 9 in moving the parts to this ositioni was that required to nieve the cranr 20 from one side of the dead center to the other. The locking member 1 6 furnishes the right.

downwards, and as the latch moves down,

ward the crank 20 describing the arc ofv-a circle, throws the upper end,of the latch to When the crank has rotated to the right to such a position that the in 19 is vto the right of 'a line oining the hoo 17 and its shaft 21, the surface of the latch 18 is nearly in engagement with the pin 25, and as the latch moves downward and the upper end thereof moves to the right, the latch eventually engages the pin 25v and begins to move aboutit as a pivot, giving a turning las well as la sliding movement to the latch' 18,'

It is apparent that my invention may-beA embodied in many different forms and I,

. therefore, do not wish to be restricted to the specific arrangement shown and'described, but'intend to cover bythe terms of the claims all changes and modifications which Y. are within the scope and spirit of my invention.

What I claim as new am. desire'to secure `by Letters Patent of the United States, is,

1. In a tripping mechanism, the-combination with a latch for engaging a locking meinber, of controlling mean for causing the .strain exerted on the latch bysaidmember to force the latch either toward or away from' latching position. Y Y 2. In a tripping mechanism, the combina? tion with a latch engaging a locking member and, shifted thereby when said member moves from locked osition, of controlling means movable relative to said latch and cooperating-therewith as said latch is shifted to force it toward latcliing position when said means is in one position and to force it away from latching position when said means is in another position.

3, In a tripping mechanism, the combina# tion with a latch engaging a locking member latcliing position.

and shifted thereby when the said member moves from Vlocked position, of controlling means coperating with said latch and movable relative thereto, and electromagnetic means for altering the relative position of the latch and the controlling means to cause the shifting of the latch by the locking meinber to force the latch toward or away from 4.J In a tripping mechanism, the combination with a latch engaging a locking meinberand shifted thereby when the said member .moves from locked position, of pivoted controlling means foi said latch movable rela-c rive thereto to change the relation of the latch to the pivot of the controlling means, whereby the shifting of the latch by .the lockin member forces the latch toward or away om locking position.

5. In a tripping mechanism, the combination with a latch engaging a locking member and shifted therebywhenthe said member moves from locking position, of pivoted controlling means for said latch movable relative thereto to. change the relation of the latch to the pivot of the controlling means, whereby the shiftingof the latch'by the locking member forces the latch toward or away lfrom latching position, and electromagnetic means for changing the relation of said latch to the pivot ofthe controlling means. y

6. In a tri ping mechanism, the combination with a atch having a hook engaging a locking member and shifted therebyv when lsaid member moves'from locking position, of

, a controlling member pivoted to said latch,

a pivot for said member mounted approxi-l mately in line between said hook and the point of attachment of the latch to the member and in engagement with the latchwhen the latch is in latching position', and means for changing the relation of said pivot to the line joining said hook and said point of attachment.

7. In a-tripping mechanism, the combination of a latch, a pivoted member coperating therewith to form a toggle, and means'V for causing movement ofthe 'toggle' toward overset osition to force" the engaging end of the latch toward latching position.

i 8.- In a tripping mechanism, the combinationf'of a latch, a vpivoted member coperating therewith to form a tripping toggle,and means cooperating with said latch to force it toward latching position as said toggle moves toward overset position and towards tripping position as said toggle moves toward under* set position.

ing therewith to form a tri ping toggle, said latch beingengaged by t e pivot of said member and forcedtoward latching position as said toggle moves toward overset position, and a pin engaged by the latch as the toggle moves toward underset position to throw said latch toward tripping-position.

9. In a. tripping mechanism, the combina- 1l.' In s, rigsmg ineelianism, 'elle combina- 'Lien with :L oted member forming one iinl: ol toggle, olf latch forming llie other link of lflie toggle :md engaging the looking member, a stop on. one side of the latch for engaging and forcing it toward latehiiig position :is the lsoggle moves toward overset position :and :1, stop on 'Llie other side of the ls-teli for 's elm/,me

ln witness whereof, l. have hereunto se?d my hand this li day ei Jmmzii'yl. 3.907.

PAUL BEHR. 1lWitnesses JULiUs R Us'. MND, KARL G. RIG/HEREN. 

